Hi > On Feb 15, 2018, at 9:03 AM, jimlux <jim...@earthlink.net> wrote: > > On 2/14/18 6:51 PM, Tim Lister wrote: >> On Feb 14, 2018 19:47, "Chris Caudle" <ch...@chriscaudle.org> wrote: >> On Wed, February 14, 2018 7:06 pm, jimlux wrote: >>> At substantially more expense, and with an experimental lattice clock, >> Does that schematic figure in the paper imply that the "transportable" >> strontium and ytterbium clocks are built into trailers instead of the >> traditional rack enclosure? >> Actually now that I look more closely it looks like maybe two trailers. >> Doesn't seem like something that Jim is going to be flying any time soon. >> Yes. From the Nature article text: >> "The transportable 87Sr lattice clock is (compared with laboratory clocks) >> designed to be compact, with robust optical parts12 >> <https://www.nature.com/articles/s41567-017-0042-3#ref-CR12>. The physics >> package is less than 0.6 m3 in size, and we use laser breadboards with >> mechanical stress-resistant fibre couplers21 >> <https://www.nature.com/articles/s41567-017-0042-3#ref-CR21>. All >> components except the reference cavity of the interrogation laser are >> rigidly mounted in a car trailer (size 2.2 m × 3 m × 2.2 m), and vibration >> isolation is provided by rubber dampers. The trailer interior is >> temperature stabilized, while the small volume of the trailer hinders air >> exchange and generates hot spots with more than 10 K temperature rise. >> However, the optics and the physics package are placed apart and shielded >> from these and are stable to within 0.4 K after an initial temperature rise >> of about 1 K. The transportable ultrastable reference cavity for the clock >> interrogation lasers is rigidly mounted to endure transport12 >> <https://www.nature.com/articles/s41567-017-0042-3#ref-CR12>. It was placed >> next to the trailer to avoid its performance being degraded by vibrations >> induced in the trailer’s air conditioning system. The vibration amplitudes >> in the trailer are a factor of ten larger than under typical laboratory >> conditions, leading to a corresponding increase in clock instability. A >> reference resonator with lower acceleration sensitivity or an active >> feed-forward system may in the future remedy this inconvenience22 >> <https://www.nature.com/articles/s41567-017-0042-3#ref-CR22>." > > > We have discussed the desirability of suitable caves for operation of high > quality clocks many times on this list. > Clearly this is another instance.
Search the archives for “swimming pool full of mercury” for one go around on this. Bob > > With respect to flying such things in space - this is the continual challenge > - DSAC (the trapped mercury ion clock) was a couple of benches in a special > time keeping lab when I first saw it, oh, a decade ago?. It will fly later > this year and it's probably about the size of an airplane carry-on. > https://www.jpl.nasa.gov/missions/deep-space-atomic-clock-dsac/ > > Cold Atom Laboratory basically takes several optical benches operated by a > team of post-docs that makes Bose Einstein Condensates (BEC) and turns it > into a box the size of a dorm refrigerator that goes "ping" when you press a > button and makes a BEC (in either Rb or K, as you choose). > > https://coldatomlab.jpl.nasa.gov/mission/ > > Just as a rule of thumb, I've found that it takes about 10-20 times the cost > to get from "benchtop prototype"(TRL 5) to "flyable unit" (TRL 6), as it cost > to get from idea to benchtop prototype. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
